Hello,
I have exactly the same problem than al8: I opened a ticket because GrimeFighter is not working for me too. I'm still waiting any answer...
I was very happy of Avast software until now.
All this messages about this one confirm that was a huge mistake to download and worst to pay for this!
Anyway, I will stop to recommend Avast! to my friends. This is absolutely unrespectful and a serious lack of professionalism.